The compressor for drawing, compressing, and discharging a working fluid carries out compression of refrigerant gas passed through an evaporator to a high pressure and a high temperature in a refrigerating system of a refrigerator or an air conditioner. Particularly, of the compressors, one in which a motor mechanism part for generating a driving force is enclosed together with a compression mechanism part is called as a hermetic compressor. The hermetic compressors may be sorted, depending on a type of the compression mechanism part, as rotary compressors, reciprocating compressors, and scroll compressors, and the like, of which hermetic reciprocating compressor will be explained, with reference to the attached drawings. FIG. 1 illustrates a section of a related art hermetic reciprocating compressor.
Referring to FIG. 1, the related art hermetic reciprocating compressor is provided with a motor mechanism part for having a current applied thereto to generate a rotating force, and a compression mechanism part for compressing a refrigerant gas by using the rotating force from the motor mechanism part, both of which are enclosed in a shell 1 to form an enclosed space. The motor mechanism part has a stator 3 supported by springs seated on a bottom of the enclosed shell 1, and a rotator 4 inserted in the stator. The compression mechanism part, positioned in an upper part of the stator 3, has a cylinder block ‘B’ having a cylinder 5 for compression of the refrigerant gas on one side thereof and an inserting hole 6, a crankshaft 7 press fit in the inserting hole in the rotator 4 with an eccentric part 7a on a top thereof, a piston 8 for reciprocating in the cylinder, and a connecting rod 9 connected between the piston and the eccentric part of the crankshaft, for converting a rotating motion of the crankshaft into a reciprocating motion of the piston. The compression mechanism part has a valve assembly ‘V’ fitted to an end of the cylinder 5 for regulating flow of refrigerant to/from the cylinder 5, and a head cover 10 covered on the valve assembly to form a plenum, a flow passage of the refrigerant discharged from the valve assembly, further. There is a silencer 11 on one side of the head cover 10 in communication with an inside of the cylinder 5, for attenuating noise and guiding the refrigerant gas to the cylinder. There is an inlet tube 12 at one side of the shell 1 with an end thereof in the vicinity of an inlet to the silencer 11 for introduction of the refrigerant gas, and an outlet tube (not shown) at the other side of the shell for discharging the refrigerant gas. There is refrigerant oil fill in a bottom of the shell 1 for prevention of wear of various mechanical components.
Upon application of power to the hermetic reciprocating compressor, the rotor rotates by an interaction between the stator 3 and the rotor 4, to rotate the crankshaft 7. During rotation of the crankshaft 7, the connecting rod 9 coupled to the eccentric part 7a converts the rotating motion into a linear reciprocating motion, to move the piston 8 in the cylinder 5. In this instance, the refrigerant gas introduced through the inlet tube 12 flows to an inside of the cylinder 5 through the silencer 11 by the motion of the piston 8 and regulation of the valve assembly, compressed to a high temperature and a high pressure, and discharged through a outlet tube. FIG. 2 illustrates a disassembled perspective view of a related art valve assembly.
Referring to FIG. 2, the related art valve assembly is provided with a head 20 between an end of the cylinder 5 and the head cover 10, a suction valve 30 between the end of the cylinder and the head, and discharge means (not shown) between the head and the head cover. The head 20 has a body plate 21 with a thickness and an area having an inlet 22 and an outlet in one side thereof. The suction valve 30 has a thin plate 31 with an area the same with the body plate 21 having a slit 32 formed therein at a position opposite to the inlet 22, flap 33 for open/closing the inlet 22 by opening/closing the slit 32, and an outlet 34 formed opposite to the outlet 23 in the head on one side of the flap 33. Though not shown, the discharge means has a discharge valve for opening/closing the outlet in the head, a valve spring for reinforcing a rigidity of the discharge valve, and a retainer for limiting behavior of the discharge valve and the valve spring. The foregoing valve assembly ‘V’ is assembled by means of a plurality of fastening bolts 13 in a state the suction valve 30, the head 20, the discharge means, and the head cover 10 are fitted in the order to the end of the cylinder 5.
The Operation of the Valve Assembly will be Explained.
When the piston 8 moves from a top dead center to a bottom dead center in the cylinder 5, the flap. 33 on the suction valve 30 is bent by a suction force in the cylinder to open the inlet 22 in the head 20, when the refrigerant gas passed through the inlet tube and the silencer 11 in succession is introduced into the cylinder. Next, when the piston 8 moves from the bottom dead center to the top dead center, the flat 33 on the suction valve is restored to an original state, to close the inlet 22 in the head. On the same time with this, a pressure of the refrigerant gas in the cylinder 5 is built up gradually until a preset pressure is reached, when the discharge valve is opened by the pressure. Then, the refrigerant gas compressed in the cylinder is discharged to outside of the cylinder through the plenum via the outlet 34 in the suction valve 30 and the outlet 23 in the head.
However, the Related Art Valve Assembly has the Following Disadvantages.
First, even though only work required from the suction valve 30 is opening/closing of the inlet 22 in the head, the suction valve 30 has a size the same with the body plate 21 of the head. It means that the suction valve 30 has a size relatively greater than the required work thereof leading to increase a fabrication cost. And, due to above reason, the thin plate 31 is required to have the slit 32 at a position opposite to the inlet 22 in the head, and an outlet 34 at a position opposite to the outlet 23 in the head, due to which a structure of the suction valve 30 becomes complicate, and fabrication and assembly steps are increased to drop a productivity. The foregoing problems are applicable also to the discharge means.
Second, the slit 32 in the suction valve for the flap 33 forms a dead space, that is a main reason of a refrigerant compression efficiency drop.